1. Field of the Invention
The present invention relates to a brake device for a vehicle and, in particular, relates to a brake booster control device in a brake device and a method of controlling the same.
2. Conventional Art
JP-A-2000-289592, for example, discloses a pressurized booster controlled by a microcomputer provided with a stroke sensor for detecting a control amount of a brake pedal and a brake pedal pressing force sensor and further discloses a brake control device for a vehicle provided with braking judgement means for judging brake pedal pressing by a driver based on the operating condition of these sensors.
However, in the brake control device for a vehicle disclosed in JP-A-2000-289592, there was a problem that such as the stroke sensor for detecting a control amount of a brake pedal and the brake pedal pressing force sensor have to be installed. Accordingly, there arose problems that time for attaching these sensors and for attachment position adjustment and a complex structure for the attachment are additionally required.
The present invention is achieved in view of the above problems and an object of the present invention is to provide a brake booster control device and a method of controlling the same which can judge whether a driver has pressed a brake pedal without installing a special sensor such as a stroke sensor and a brake pedal pressing force sensor.
Namely, a brake booster control device according to the present invention which achieves the above object includes a function of judging that a driver has pressed a brake pedal based on at least one of the following information is obtained, in that when an output (a master cylinder pressure) lager by a predetermined amount than an output (master cylinder pressure) which is expected from a control amount applied to a control valve is obtained, when an output larger by a predetermined amount than a control target output (target master cylinder pressure) is obtained and when an output variation larger in its increasing direction by a predetermined amount than a variation component of a control target output (target master cylinder pressure) is obtained, thereby, a provision of the stroke sensor and the brake pedal pressing force sensor is eliminated. As a result, the structure of a booster is simplified and the attachment work and the attachment position adjustment work of the stroke sensor and the brake pedal pressing force sensor are also eliminated.